Rabbi Mark Winer returned to live in the United States last autumn after his retirement as West London Synagogue's senior minister.
But he has not left Britain behind, having just concluded a 10-day visit here on behalf of his new enterprise, Faith - the Foundation to Advance Interfaith Trust and Harmony.
It included addresses to both the East London Mosque/London Muslim Centre in Whitechapel and a Sayeda Fatima conference, a celebration of the Prophet Muhammad's daughter at the House of Lords.
"The mosque has had rabbis to meetings before," he said. "But this is the first time they've had a rabbi to speak and publicised it."
An audience of 40 attended his mosque talk, defying a small cluster of militants outside the building demonstrating against interfaith dialogue.
His hosts were "more jumpy" about the protesters than he was. "I am willing to talk to anybody. Nobody scares me," said the six foot five inch, 17-stone rabbi.
But he noted that supporters of the mosque are among the Jewish, Muslim and Christian donors who have pledged more than £1 million to Faith over the past six months. At the Lords, he extolled the contribution of women towards interfaith understanding to an audience of largely Muslim women with "lovely hijabs and the highest heels you ever saw".
The foundation, which has branches here and America, had got off to a "great start", he said. It has already produced an educational DVD on Moses, the first in a planned series on seminal figures from the three Abrahamic traditions. A declared "Islamophile", he said that his study of Islam and friendship with Muslims had become "the highest calling of my work as a rabbi". But he made it clear to his audiences that it was from Jewish friends in Israel that he first learned "to appreciate Islam, to befriend Arabs and to appreciate Arab culture, language and food".
Christians and Muslims "need to appreciate the Jewish attachment to the land and language of their ancestors".
Jewish support for his bridge-building activities is by no means universal. But opposition will not deter him. "Fifty years ago people would have laughed at the idea that there would be diplomatic relations between Israel and the Vatican," he said. "We are a people wedded to hope. That is why our national anthem is Hatikvah [the hope]."